Potential Pathogenic Mutation Found

Potential Pathogenic Mutation Found

The researchers doubt that a large proportion of the millions of people who suffer from the syndrome have this mutated MEIS1 gene. They point out, however, that understanding the function of both the normal and abnormal genes will shed some insights into this mysterious disorder.

Restless legs syndrome affects between 5 and 11 percent of the population in Europe and in North America. The condition is characterized by unpleasant sensations in the legs at rest, especially in the evening, that are temporarily relieved by movement. Because restless legs syndrome often interrupts sleep, people commonly are diagnosed after they consult a sleep specialist for assistance.

"We think restless legs syndrome may be due to a number of clinical factors, but we also believe that there is a strong genetic component to the disorder," says the study's lead investigator, Carles Vilariño-Güell, Ph.D., a neuroscientist at Mayo Clinic, Jacksonville.

"The mutation we found is in a portion of the protein that is identical in species as distinct to human as frogs and fish, which tells us that this portion is very important for the proper function of the protein and that the mutation has a very high chance of causing disease," he says.

While common variants (different versions) of MEIS1 and BTBD9, another associated gene, have been found in families with a high incidence of restless legs syndrome, it is not clear that those variants are capable of causing disease, Dr. Vilariño-Güell says.

"This mutation, on the other hand, is the first that we think can be a real candidate for causing or promoting restless legs syndrome," he says.